A capacitor for a CPU (Central Processing Unit) for use in a personal computer or the like is required to be high in capacity and low in ESR (Equivalent Series Resistance) in order to control fluctuation in voltage and reduce heat generation at the time of passing high ripple currents. As such a capacitor, for example, an aluminum solid electrolytic capacitor and a tantalum solid electrolytic capacitor are used. Such a solid electrolytic capacitor is known to have a structure including one electrode (electric conductor) of an aluminum foil having a surface layer with minute pores or a sintered compact obtained by sintering tantalum powder having minute pores inside thereof, a dielectric layer formed on a surface of the electrode, and another electrode (normally, semiconductor layer) formed on the dielectric layer.
In a solid electrolytic capacitor, a method is known in which a dielectric layer is formed on a surface of a conductive member by electrically connecting one end of a lead wire extended from a conductive member to a metallic connection terminal of a socket attached to a lower end portion of a circuit board having an electric circuit, immersing the conductive member in chemical conversion treatment liquid, and passing a current between the conductive member as a positive electrode and a cathode (negative) electrode arranged in the chemical conversion treatment liquid, and then a semiconductor layer is formed on a surface of the dielectric layer on the surface of the conductive member by immersing the conductive member having the dielectric layer formed on a surface thereof in semiconductor layer forming liquid, and passing a constant current by applying a voltage between the conductive member as a positive electrode and a cathode (negative) electrode arranged in the semiconductor forming liquid (see Patent document 1).